U.S – Researchers have underscored that identifying and reducing per- and polyfluoroalkyl substances (PFAS) exposure sources should be a top concern for public health after their study found alarming levels of the compound in U.S freshwater fish.
According to the study’s findings, eating one dish of fish might have the same negative health effects as consuming significantly contaminated water for a month.
PFAS, or “forever chemicals,” are chemicals present in consumer goods that have been linked to harmful effects on human health and are becoming more common in the environment.
One of the main ways that people are exposed to PFAS is through the consumption of contaminated food and water, which causes PFAS to build up in the body.
Researchers in the study estimated the possible contribution of perfluorooctanesulfonic acid (PFOS), a form of PFAS, from the consumption of locally caught freshwater fish to levels of the chemicals in human blood serum.
Data from more than 500 fish fillet composite samples collected nationwide between 2013 and 2015 as part of the National Rivers and Streams Assessment and the Great Lakes Human Health Fish Fillet Tissue Study monitoring programs run by the U.S. Environmental Protection Agency (EPA) were evaluated.
Based on data analysis, fish fillets from rivers and streams across the United States had a median total targeted PFAS concentration of 9,500 nanograms per kilogram (ng/kg), with a median level of 11,800 ng/kg in the Great Lakes.
With a median level of 11,800 ng/kg in the Great Lakes, analysis of the data showed that the median level of total targeted PFAS in fish fillets from rivers and streams across the U.S. was 9,500 ng/kg.
Additionally, there was no detectable PFAS in any of the 349 samples examined for the National Rivers and Streams Assessment.
Overall, it was shown that PFOS, which accounts for an average of 74% of the total, is the main source of PFAS levels.
The U.S. Food and Drug Administration’s (FDA) tests on commercially relevant retail fish revealed that the median levels of total PFAS discovered in freshwater fish across the country were 278 times higher.
A single serving of freshwater fish per year (with the median level of PFAS as identified by the U.S. EPA monitoring programs) is thought to significantly raise the levels of PFOS in human blood serum, according to exposure assessment based on the data.
Human blood serum PFOS levels show that consuming one dish of fish can be similar to consuming 48 parts per trillion (ppt) of PFOS in a month’s worth of water.
Since certain commercially caught fish are raised in carefully regulated aquaculture facilities or far offshore in the ocean where pollution is more dilute, researchers predict that the PFAS levels in fish as revealed by the current study are lower than those found by the FDA.
Moreover, freshwater pollution levels may be declining as PFAS use in industry is gradually phased out.
Nevertheless, PFAS contamination levels in human blood serum are currently high enough to affect the ingestion of any freshwater fish.
Last but not least, the researchers emphasize how little information is available in the US about safe fish consumption, with only 14 out of 50 states having issued a PFAS-specific fish consumption advisory.
They also encourage future studies on the effects of various PFAS exposure pathways on blood serum levels as well as PFAS concentrations in food and locally caught fish.
PFAS have no national standard for dietary exposure, reports Food Quality & Safety.